Hybrid drive device

ABSTRACT

There is provided a first and second bearing supporting a clutch case at first and second axial sides in a radial direction, a rotor of a rotary electrical machine is supported by the clutch case, a gap between an outer peripheral face of a pump drive shaft 10 and an inner peripheral face of a drive shaft insertion hole  90   c  is a distribution passage L of oil flowing from a pump chamber  18   a  to the first bearing  51 , and a distribution passage diameter difference, which is a difference between a diameter Φa of the outer peripheral face of the pump drive shaft 10 and a diameter Φc of the inner peripheral face of the drive shaft insertion hole  90   c  in the distribution passage L, is set so that the distribution passage L functions as a narrowed portion which limits a flow rate of oil.

INCORPORATION BY REFERENCE

The disclosure of Japanese Patent Application No. 2010-083055 filed onMar. 31, 2010 including the specification, drawings and abstract isincorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

The present invention relates to a hybrid drive apparatus including afirst shaft drive-coupled to an internal combustion engine, a secondshaft drive-coupled to a speed change mechanism, a clutch drive-coupledselectively to the first shaft and the second shaft, a rotary electricalmachine, and a case housing the clutch and the rotary electricalmachine.

DESCRIPTION OF THE RELATED ART

As the above-described hybrid drive apparatus, for example, there hasbeen already known a device illustrated in FIG. 7 of Japanese PatentApplication Publication No. 2009-1127. As illustrated in FIG. 7 ofJapanese Patent Application Publication No. 2009-1127, in this hybriddrive apparatus, an engine input shaft 10 (first shaft) drive-coupled toan engine 2 (internal combustion engine) and a transmission input shaft45 (second shaft) drive-coupled to a belt-type continuously variabletransmission (speed change mechanism) are structured to be capable ofbeing selectively drive-coupled via a clutch 49. The clutch 49 is housedin a casing formed by joining a front cover 24 and a rear cover 102. Acylindrical part 38 provided on the rear cover 102 is disposedpenetrating a body 35 of an oil pump 34 to engage with a rotor 37disposed in a pump chamber, and the oil pump 34 is driven by rotation ofthe casing. That is, the cylindrical part 38 is a pump drive shaftdriving the oil pump 34. In addition, the cylindrical part 38 issupported rotatably on the body 35 via a bush disposed between an outerperipheral face of the cylindrical part 38 and an inner peripheral faceof the body 35.

SUMMARY OF THE INVENTION

Now, in the structure illustrated in FIG. 7 of Japanese PatentApplication Publication No. 2009-1127, the cylindrical part 38penetrates the body 35 and extends to the pump chamber, and there is agap between the outer peripheral face of the cylindrical part 38 and theinner peripheral face of the body 35. Thus, part of oil increased inpressure in the pump chamber passes through this gap and leaks to thebush side in an axial direction. Such a leak of oil affects the amountof oil to be discharged via a discharge chamber from the pump chamber,and thus the structure is desired to be capable of limiting the amountof leaking oil via the gap.

However, Japanese Patent Application Publication No. 2009-1127 describesthat an oil seal 39 is on the opposite side of the bush from the pumpchamber in the axial direction, thereby preventing oil leakage to thespace in which a motor-generator 3 (rotary electrical, machine) isdisposed. However, there is no description mentioning about limiting theamount of oil leaking from the pump chamber 38 through the gap betweenthe outer peripheral face of the cylindrical part 38 and the innerperipheral face of the body 35. Accordingly, as a matter of course,Japanese Patent Application Publication No. 2009-1127 does not describea mechanism for limiting the amount of leaking oil via the gap.

Accordingly, achievement of a hybrid drive apparatus is desired, whichis capable of limiting the amount of oil leaking in the axial directionalong the outer peripheral face of the pump drive shaft from the pumpchamber.

A hybrid drive apparatus according to a first aspect of the presentinvention includes: a first shaft drive-coupled to an internalcombustion engine; a second shaft drive-coupled to a speed changemechanism; a clutch drive-coupled selectively to the first shaft and thesecond shaft; a rotary electrical machine; a case housing the clutch andthe rotary electrical machine; a clutch case drive-coupled to one of thefirst shaft and the second shaft and housing the clutch; an oil pumpincluding a pump case fixed to the case and forming a pump chamberinside and a pump rotor arranged rotatably in the pump chamber, the oilpump being arranged coaxially with the clutch case on one axial sidewith respect to the clutch case; a first bearing supporting the clutchcase at one axial side in a radial direction on the case; and a secondbearing supporting the clutch case at another axial side in the radialdirection on the case, in which a rotor of the rotary electrical machineis supported by the clutch case, the first bearing includes an outerwheel, an inner wheel, and rolling elements intervening between theouter wheel and the inner wheel, the clutch case includes a pump driveshaft which extends toward one axial side and is drive-coupled to thepump rotor, the pump drive shaft is supported on the case via the firstbearing and the pump case, the pump case includes a partition wallpartitioning the first bearing and the pump rotor, the partition wallincludes a drive shaft insertion hole through which the pump drive shaftis inserted, a gap between an outer peripheral face of the pump driveshaft and an inner peripheral face of the drive shaft insertion hole isa distribution passage of oil flowing from the pump chamber to the firstbearing, and a distribution passage diameter difference, which is adifference between a diameter of the outer peripheral face of the pumpdrive shaft and a diameter of the inner peripheral face of the driveshaft insertion hole in the distribution passage, is set so that thedistribution passage functions as a narrowed portion which limits a flowrate of oil.

According to the first aspect of the present invention, the distributionpassage diameter difference is set so that the distribution passage,which is a route of oil when oil leaks in the axial direction along theouter peripheral face of the pump drive shaft from the pump chamber,functions as the narrowed portion which limits the flow rate of oil.Thus, the amount of oil leaking in the axial direction along the outerperipheral face of the pump drive shaft from the pump chamber can belimited, and the amount of oil discharged via a discharge chamber fromthe pump chamber can be secured properly.

Note that since it is unnecessary to dispose a dedicated member forlimiting the flow rate of oil in the distribution passage, it is alsopossible to suppress the size in the axial direction and the cost of thehybrid drive apparatus to increase.

Further, the clutch case including the pump drive shaft is supported inthe radial direction on the case at both sides in the axial direction bythe first bearing and the second bearing. Moreover, the first bearingsupporting the one axial side on which the pump drive shaft of theclutch case is provided is a bearing having an outer wheel, an innerwheel, and rolling elements, for which a bearing having high supportingprecision in the radial direction compared to a bearing having norolling element is employed. Accordingly, in this structure, it ispossible to support the clutch case precisely in the radial direction,and it is easy to suppress displacement in the radial direction of theouter peripheral face of the pump drive shaft provided in the clutchcase within a relatively narrow range. Further, the drive shaftinsertion hole which is one member sectioning the distribution passagein the radial direction is provided in the pump case fixed to the case.That is, in this structure, a radial direction width of a gap betweenthe outer peripheral face of the pump drive shaft and the innerperipheral face of the drive shaft insertion hole can be maintainedwithin a relatively narrow range with a value decided according to thedistribution passage diameter difference being a center. Therefore, inthis structure, while suppressing a contact between the outer peripheralface of the pump drive shaft and the inner peripheral face of the driveshaft insertion hole, it is easy to set the distribution passagediameter difference to a minimal value so that the distribution passagefunctions properly as the narrowed portion.

According to a second aspect of the present invention, the distributionpassage diameter difference may be set larger than a maximum value of anallowance of displacement in the radial direction of the pump driveshaft supported by the first bearing, and the distribution passagediameter difference may be set so that a flow passage sectional area ofthe distribution passage is smaller than a flow passage sectional areaof a pump flow passage which is formed by a gap between the partitionwall and the pump rotor and communicates with the distribution passage.

In this structure, since the distribution passage diameter difference isset larger than the maximum value of an allowance of displacement in theradial direction of the pump drive shaft supported by the first bearing,a contact between the outer peripheral face of the pump drive shaft andthe inner peripheral face of the drive shaft insertion hole can besuppressed. Further, since the flow passage sectional area of thedistribution passage is smaller than the flow passage sectional area ofthe pump flow passage, it is possible in this structure to dischargeinto the distribution passage only part of oil which is not dischargedfrom the discharge chamber but flows through the pump flow passage.Therefore, while suppressing a contact between the outer peripheral faceof the pump drive shaft and the inner peripheral face of the drive shaftinsertion hole, the distribution passage can function properly as thenarrowed portion.

According to a third aspect of the present invention, the pump driveshaft may be formed in a stepped shape with one axial side being a smalldiameter portion and another axial side being a large diameter portion,and may be arranged so that the inner peripheral face of the drive shaftinsertion hole faces an outer peripheral face of the small diameterportion, the first bearing may be arranged in contact with an outerperipheral face of the large diameter portion, a difference between adiameter of the large diameter portion and a diameter of the smalldiameter portion may be designated as a pump shaft step width, and thedistribution passage diameter difference may be set to a value largerthan a maximum value of an allowance of displacement in the radialdirection of the pump drive shaft supported by the first bearing andsmaller than the pump shaft step width.

In this structure, since the distribution passage diameter difference isset larger than the maximum value of an allowance of displacement in theradial direction of the pump drive shaft supported by the first bearing,a contact between the outer peripheral face of the pump drive shaft andthe inner peripheral face of the drive shaft insertion hole can besuppressed. Further, since the distribution passage diameter differenceis set to a value smaller than the pump shaft step width, it is easy inthis structure to arrange the inner peripheral face of the drive shaftinsertion hole at a position close on a radially outer side to the outerperipheral face of the small diameter portion. Thus, a gap between theinner peripheral face of the drive shaft insertion hole and the outerperipheral face of the small diameter portion can be made as a minimalspace. While suppressing a contact between the outer peripheral face ofthe pump drive shaft and the inner peripheral face of the drive shaftinsertion hole, the distribution passage can function properly as thenarrowed portion.

According to a fourth aspect of the present invention, the pump driveshaft may include a supply oil passage inside that supplies oil to theclutch, the pump case may include a section wall which is arranged onthe opposite side of the pump rotor from the partition wall in the axialdirection and sections one axial side of the pump chamber, and a sectionwall side pump flow passage formed by a gap between the section wall andthe pump rotor may communicate with the supply oil passage.

In this structure, oil which is not discharged to the distributionpassage due to that the distribution passage functions as the narrowedportion can be actively guided to the supply oil passage for supplyingoil to the clutch. Thus, by securing a discharge destination of oilflowing in the pump chamber without being discharged from the dischargechamber, the amount of oil discharged to the distribution passage can belimited properly, and oil which is not discharged from the dischargechamber and flows in the pump chamber can be utilized effectively.

According to a fifth aspect of the present invention, the clutch casemay include a one-side radially extending portion arranged on one axialside of the clutch to extend in the radial direction and having aradially inner end portion on which the pump drive shaft is provided, ananother-side radially extending portion arranged on another axial sideof the clutch to extend in the radial direction, and a cylindricalaxially extending portion arranged on a radially outer side of theclutch to extend in the axial direction, the rotary electrical machinemay be arranged coaxially with the clutch case and the rotor of therotary electrical machine is fixed in contact with an outer peripheralface of the axially extending portion, the another-side radiallyextending portion and the axially extending portion may be formedintegrally, the one-side radially extending portion and the axiallyextending portion may be joined by welding and integrated, and a joiningpart by welding may be located on a radially outer side with respect toan inner peripheral face of the rotor.

In this structure, the joining part by welding can be at a positionapart in the radial direction from the pump drive shaft. Thus, it ispossible to suppress deformation of the pump drive shaft and theone-side radially extending portion, on which the pump drive shaft isprovided on the radially inner end portion, by heat during the welding.Therefore, the gap between the outer peripheral face of the pump driveshaft and the inner peripheral face of the drive shaft insertion holecan be suppressed from becoming uneven in the circumferential directionor from becoming locally too large or too small, and the function of thecommunication passage as the narrowed portion can be achieved as adesired function.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram illustrating a schematic structure of ahybrid drive apparatus according to an embodiment of the presentinvention;

FIG. 2 is a partial cross-sectional view of the hybrid drive apparatusaccording to the embodiment of the present invention; and FIG. 3 is apartially enlarged view of FIG. 2.

DETAILED DESCRIPTION OF THE EMBODIMENTS

An embodiment of a hybrid drive apparatus according to the presentinvention will be described with reference to the drawings. The hybriddrive apparatus 1 is a drive apparatus for a hybrid vehicle using one orboth of an internal combustion engine E and a rotary electrical machineMG as a driving force source of the vehicle. This hybrid drive apparatus1 is structured as a hybrid drive apparatus of what is called one motorparallel type.

The hybrid drive apparatus 1 according to this embodiment includes, asillustrated in FIG. 1, an input shaft I drive-coupled to an internalcombustion engine, a rotary electrical machine MG, an intermediate shaftM drive-coupled to a speed change mechanism TM, a clutch CL whichselectively drive couples the input shaft I and the intermediate shaftM, and a case 2 housing the clutch CL and the rotary electrical machineMG. In such a structure, the hybrid drive apparatus 1 according to thisembodiment has characteristics in that a clutch case CH is supported ina radial direction on the case 2 at both sides in an axial direction(see FIG. 2), and that a distribution passage L formed by a gap betweenan outer peripheral face of a pump drive shaft 10 and an innerperipheral face of a drive shaft insertion hole 90 c (see FIG. 3) isstructured to function as a narrowed portion which limits a flow rate ofoil. Thus, it is possible to limit the amount of oil leaking from a pumpchamber 18 a in the axial direction along the outer peripheral face ofthe pump drive shaft 10. Hereinafter, the hybrid drive apparatus 1according to the present invention will be described in detail.

Note that in the following description, unless otherwise specified,“axial direction or axially”, “circumferential direction orcircumferentially”, and “radial direction or radially” are defined onthe basis of the rotation axes of the input shaft I and the intermediateshaft M arranged coaxially. These rotation axes match the rotation axesof respective rotation elements provided in the clutch CL, the clutchcase CH, an inner rotor 18 b provided in an oil pump 18, and a rotor Roprovided in the rotary electrical machine MG Further, in the followingdescription, unless otherwise specified, the left side in FIG. 2 isdesignated as “one axial side”, and the right side in FIG. 2 isdesignated as “another axial side”.

1. The Overall Structure of the Hybrid Drive Apparatus

First, the overall structure of the hybrid drive apparatus 1 accordingto this embodiment will be described. As illustrated in FIG. 1, thishybrid drive apparatus 1 includes an input shaft I drive-coupled to aninternal combustion engine E as a first driving force source of thevehicle, a rotary electrical machine MG as a second driving force sourceof the vehicle, a speed change mechanism TM, an intermediate shaft Mdrive-coupled to the rotary electrical machine MG and also drive-coupledto the speed change mechanism TM, and output shafts O drive-coupled towheels W. Further, the hybrid drive apparatus 1 includes a clutch CLprovided to be capable of switching transmission and disconnection ofdriving force between the input shaft I and the intermediate shaft M, acounter gear mechanism C, and an output differential gear device DF.These structures are housed in a case 2 serving as a drive apparatuscase. In this embodiment, the input shaft I and the intermediate shaft Mfunction as a “first shaft” and a “second shaft” respectively in thepresent invention.

Note that being “drive-coupled” refers to a state that two rotationelements are coupled to be capable of transmitting driving force, and isused as a concept including a state that these two rotation elements arecoupled to rotate integrally or a state that the two rotation elementsare coupled to be capable of transmitting driving force via one or moretransmission members. Such transmission members include various types ofmembers which transmit rotation at the same speed or after shifting thespeed thereof, and include, for example, a shaft, a gear mechanism, abelt, a chain, and the like. Further, “driving force” is used for thesame meaning as torque. A “rotary electrical machine” is used as aconcept including any one of a motor (electric motor), a generator(power generator), and a motor-generator performing both functions of amotor and a generator as necessary.

The internal combustion engine E is a device driven by combustion offuel inside the engine to extract motive power, and for example, one ofvarious publicly known engines, such as gasoline engines and dieselengines, can be used. In this example, an internal combustion engineoutput shaft Eo such as a crankshaft of the internal combustion engine Eis drive-coupled to the input shaft I via a damper D. Further, the inputshaft I is drive-coupled to the rotary electrical machine MG and theintermediate shaft M via the clutch CL, and the input shaft I isdrive-coupled selectively to the rotary electrical machine MG and theintermediate shaft M by the clutch CL. In an engagement state of theclutch CL, the internal combustion engine E and the rotary electricalmachine MG are drive-coupled via the input shaft I, and in a releasedstate of the clutch CL, the internal combustion engine E and the rotaryelectrical machine MG are separated.

The rotary electrical machine MG is structured to have a stator St and arotor Ro, and is capable of performing a function as a motor (electricmotor) generating motive power while receiving supply of electric powerand a function as a generator (power generator) generating electricpower while receiving supply of motive power. Thus, the rotaryelectrical machine MG is connected electrically to a power storage(not-illustrated). In this example, a battery is used as the powerstorage. In addition, it is also preferred that a capacitor or the likebe used as the power storage. The rotary electrical machine MG ispowered to rotate while receiving supply of electric power from thebattery, or supplies electric power generated from torque outputted bythe internal combustion engine E or inertial force of the vehicle forstoring the electric power therein. The rotor Ro of the rotaryelectrical machine MG is drive-coupled to the intermediate shaft M so asto integrally rotate therewith. This intermediate shaft M is an inputshaft (speed change input shaft) of the speed change mechanism TM.

The speed change mechanism TM is a device which shifts the rotationspeed of the intermediate shaft M with a predetermined speed ratio andtransmits the rotation to a speed change output gear G. As such a speedchange mechanism TM, in this embodiment, there is used an automaticspeed change mechanism which is structured to include a single-piniontype and a Ravigneaux type planetary gear mechanism and pluralengagement devices such as a clutch, a brake, and a one-way clutch, andhas plural shift speeds with different speed ratios in a switchablestructure. Note that as the speed change mechanism TM, an automaticspeed change mechanism having another specific structure, an automaticcontinuously variable speed change mechanism capable of continuouslyvarying a speed ratio, a manual stepped speed change mechanism havingplural shift speeds with different speed ratios in a switchablestructure, or the like may be used. The speed change mechanism TM shiftsthe rotation speed of the intermediate shaft M with the predeterminedspeed ratio at each time point, converts the torque, and transmits therotation to the speed change output gear G.

The counter gear mechanism C transmits the rotation and torque of thespeed change output gear G to the side of the wheels W. This countergear mechanism C is structured to have a counter shaft Cs, a first gearC1, and a second gear C2. The first gear C1 meshes with the speed changeoutput gear G The second gear C2 meshes with a differential input gearDi provided in the output differential gear device DF. The outputdifferential gear device DF splits and transmits the rotation and torqueof the differential input gear Di to the plural wheels W. In thisexample, the output differential gear device DF is a differential gearmechanism using plural bevel gears meshing with each other, and splitsthe torque transmitted to the differential input gear Di via the secondgear C2 of the counter gear mechanism C and transmits the split torqueto the two left and right wheels W via the respective output shafts O.Thus, the hybrid drive apparatus 1 transmits the torque of one or bothof the internal combustion engine E and the rotary electrical machine MGto the wheels W to enable the vehicle to travel.

Note that in the hybrid drive apparatus 1 according to this embodiment,the input shaft I and the intermediate shaft M are arranged coaxially,and the counter shaft Cs and the output shafts O are arranged inparallel with each other on respective axes different from the inputshaft I and the intermediate shaft M. Such a structure is suitable asthe structure of the hybrid drive apparatus 1 mounted on, for example, aFF (Front Engine Front Drive) vehicle.

2. The Structures of Respective Parts of the Hybrid Drive Apparatus

Next, the structures of respective parts of the hybrid drive apparatus 1according to this embodiment will be described. As illustrated in FIG.2, the case 2 includes a case peripheral wall 3 covering the outerperiphery of respective parts housed therein, such as the rotaryelectrical machine MG and the speed change mechanism TM, a first supportwall 4 closing an opening on another axial side (the side of theinternal combustion engine E) of the case peripheral wall 3, and asecond support wall 7 arranged between the rotary electrical machine MGand the speed change mechanism TM in the axial direction on one axialside (the side opposite to the internal combustion engine E, that is,the speed change mechanism TM side) with respect to the first supportwall 4. Moreover, this case 2 includes an end portion support wall (notillustrated) closing one axial end portion of the case peripheral wall3.

The first support wall 4 has a shape extending at least in a radialdirection, and extends in the radial direction and a circumferentialdirection in this embodiment. A through hole in an axial direction isformed in the first support wall 4, and the input shaft I insertedthrough this through hole penetrates the first support wall 4 and isinserted in the case 2. The first support wall 4 integrally has anaxially projecting portion 5 having a cylindrical shape (boss shape)projecting toward one axial side. In this example, the first supportwall 4 is a wall part having a shape curving in a dish form whichprotrudes toward the one axial side so that a radially inner portionthereof is located on the one axial side with respect to a radiallyouter portion thereof, in a portion which the input shaft I penetrates.The first support wall 4 is arranged adjacent at a predetermined spaceapart on another axial side with respect to the clutch case CH whichwill be described later. Further, to the first support wall 4, an oilpassage forming member 71 inside which a discharged oil passage 72 isformed is attached along the radial direction.

The second support wall 7 has a shape extending at least in the radialdirection and extends in the radial direction and the circumferentialdirection in this embodiment. A through hole in the axial direction isformed in the second support wall 7. Specifically, the second supportwall 7 integrally has, on its radially inner end portion, a cylindricalportion 7 a having a cylindrical form (boss shape) in its entiretyextending in the axial direction, and an inner peripheral face of thecylindrical portion 7 a defines an outer edge of the through hole formedin the second support wall 7. As will be described later, thiscylindrical portion 7 a functions as a resolver fixing part for fixing asensor stator of a resolver 19, and also functions as a positioning partwhich positions a pump case 8 (pump body 90 in this example) of the oilpump 18 in the radial direction. Further, the second support wall 7 isarranged adjacent at a predetermined space on one axial side to theclutch case CH.

The oil pump 18 is provided on a radially inner side of the secondsupport wall 7 with respect to the radial direction. Further, the oilpump 18 is provided between the speed change mechanism TM and the clutchcase CH with respect to the axial direction, in other words, between thespeed change mechanism TM and the rotary electrical machine MG. The oilpump 18 is arranged coaxially with the input shaft I and theintermediate shaft M. Further, as will be described later, also theclutch case CH is arranged coaxially with the input shaft I and theintermediate shaft M. The speed change mechanism TM is then arranged onone axial side with respect to the clutch case CH. Therefore, the oilpump 18 is arranged coaxially with the clutch case CH on the one axialside with respect to the clutch case CH.

The oil pump 18 includes a pump case 8 fixed to the case 2 and forming apump chamber 18 a inside, an inner rotor 18 b arranged rotatably in thepump chamber 18 a, and an outer rotor 18 c likewise arranged rotatablyin the pump chamber 18 a. The pump case 8 is formed by joining a pumpbody 90 arranged on another axial side and a pump cover 91 arranged onone axial side with each other. Then, a through hole in the axialdirection is formed in the pump case 8 (specifically, in both the pumpbody 90 and the pump cover 91), and the intermediate shaft M insertedthrough this insertion hole penetrates the pump case 8 (oil pump 18). Inthis embodiment, the inner rotor 18 b functions as a “pump rotor” in thepresent invention.

The pump body 90 is an annular plate-shaped member extending in theradial direction and the circumferential direction, and integrally has,on another axial end portion, an axially projecting portion 90 b havinga cylindrical shape (boss shape) projecting on another axial side.Including such an axially projecting portion 90 b, another axial side ofthe pump body 90 has a cylindrically expanding shape in its entirety,and has a shape projecting on the side of the clutch case CH and therotary electrical machine MG in the axial direction. Further, in oneaxial end face of the pump body 90, a recessed portion for forming thepump chamber 18 a is formed in a circular cross-sectional shape when itis seen from the axial direction.

As illustrated in FIG. 2, the pump body 90 is positioned in the radialdirection by fitting of an outer peripheral face of the pump body 90with an inner peripheral face of the cylindrical portion 7 a of thesecond support wall 7. Specifically, in the pump body 90, the outerperipheral face of the pump body 90 and the inner peripheral face of thecylindrical portion 7 a are arranged to face each other, and a fourthseal member 64 is interposed between the outer peripheral face of thepump body 90 and the inner peripheral face of the cylindrical portion 7a. In this example, the fourth seal member 64 is an O-ring, and isfitted in a recessed groove formed in the outer peripheral face of thepump body 90 to extend circumferentially. By thus interposing the fourthseal member 64 in between, the space between the outer peripheral faceof the pump body 90 and the inner peripheral face of the cylindricalportion 7 a of the second support wall 7 is sealed in an oil-tight(liquid-tight) state. That is, the pump body 90 is fitted inside thecylindrical portion 7 a via the fourth seal member 64 and is held inposition by the second support wall 7 in an oil-tight state.

The pump cover 91 is an annular plate-shaped member extending in theradial direction and the circumferential direction. The one axial endface of the pump body 90 and another axial end face of the pump cover 91are then joined to form the pump chamber 18 a for housing the innerrotor 18 b and the outer rotor 18 c inside the pump body 90 and the pumpcover 91. Specifically, the pump chamber 18 a is formed of theabove-described recessed portion having a circular cross-sectional shapeprovided in the pump body 90, and the other axial end face of the pumpcover 91. In this example, the pump body 90 and the pump cover 91 arefastened and fixed with each other with a fastening bolt(not-illustrated). Further, by fastening and fixing the pump cover 91onto the case 2 with a fastening bolt 81, the pump case 8 is fixed tothe case 2.

In this embodiment, the oil pump 18 is an inscribed type gear pumphaving the inner rotor 18 b and the outer rotor 18 c. The inner rotor 18b and the outer rotor 18 c are housed rotatably in a state eccentricfrom each other in the pump chamber 18 a. The inner rotor 18 b is a pumpgear arranged coaxially with the intermediate shaft M, and isdrive-coupled at its center portion in the radial direction to the pumpdrive shaft 10, which will be described later, so as to integrallyrotate therewith. In this example, as illustrated in FIG. 3, a pair ofkeys 18 d projecting from an inner peripheral face of the inner rotor 18b engage with key grooves 10 d formed in one axial end portion of thepump drive shaft 10, so as to drive couple the inner rotor 18 b to thepump drive shaft 10. Alternatively, a structure in which the inner rotor18 b and the pump drive shaft 10 are spline-coupled may be employed. Thepump drive shaft 10 is provided integrally on a member (one-sideradially extending portion 45) forming the clutch case CH and integrallyrotates with the clutch case CH, details of which will be describedlater.

Accompanying rotation of the clutch case CH, the oil pump 18 sucks inoil from a suction chamber 92 to the pump chamber 18 a to generate anoil pressure, and discharges the oil to a discharge chamber(not-illustrated). Then, the oil discharged to the discharge chamber issupplied to the clutch CL and the speed change mechanism TM, and thelike. That is, the oil pump 18 generates an oil pressure for causing theclutch CL and the speed change mechanism TM to operate. In addition,inside the pump case 8 (the pump body 90, the pump cover 91) and theintermediate shaft M, and the like, respective oil passages are formed,and the oil discharged by the oil pump 18 is distributed through a oilpressure control device (not-illustrated) and these oil passages, andsupplied to respective parts serving as oil supply targets.

Then, in this embodiment, as illustrated in FIG. 2, the space in thecase 2 is sectioned in the axial direction by the second support wall 7extending in the radial direction and the circumferential direction andthe pump case 8 (the pump body 90, the pump cover 91) likewise extendingin the radial direction and the circumferential direction. That is, thesecond support wall 7 and the pump case 8 cooperatively forms a wallpart extending in the radial direction and the circumferentialdirection, and the space in the case 2 is sectioned in the axialdirection by this wall part. Here, assuming that a space located onanother axial side with respect to this wall portion in the case is afirst chamber and a space located on one axial side is a second chamber,it can be said that the clutch CL, the rotary electrical machine MG, anda resolver 19 are housed in the first chamber, and the speed changemechanism TM is housed in the second chamber. Note that in thisembodiment, since the space between the outer peripheral face of thepump body 90 and the inner peripheral face of the cylindrical portion 7a of the second support wall 7 is sealed in an oil-tight state asdescribed above, distribution of oil between the first chamber and thesecond chamber without passing through the oil passages is basicallyprohibited. Accordingly, the hybrid drive apparatus 1 according to thisembodiment has a structure in which the space in the first chamberexcluding the inside of the clutch case CH can be kept in a dry state inwhich no oil is distributed.

Now, as will be described later, the pump case 8 (pump body 90) supportsthe clutch case CH via a first bearing 51. The first bearing 51 is thensupplied with oil leaking to another axial side through the spacebetween the pump body 90 and the pump drive shaft 10 from the pumpchamber 18 a. In the pump body 90 and the pump cover 91, a dischargedoil passage 9 for discharging oil which lubricated the first bearing 51is formed. Note that the amount of oil discharged from the oil pump 18via the discharge chamber (not illustrated) decreases according to theamount of oil leaking from the pump chamber 18 a to the other axialside, and thus the amount of leaking oil from the pump chamber 18 a isdesired to be limited to a degree capable of properly lubricating thefirst bearing 51. In the present invention, it is possible to limit theamount of oil leaking to the other axial side from the pump chamber 18 awithout arranging a dedicated member (seal member or the like) forlimiting the amount of leaking oil. This point will be described indetail in the section 3.

The input shaft I is a shaft for inputting torque of the internalcombustion engine E to the hybrid drive apparatus 1, and isdrive-coupled at another axial end portion to the internal combustionengine E. Here, the input shaft I is disposed in a state of penetratingthe first support wall 4 and, as illustrated in FIG. 2, drive-coupled tothe internal combustion engine output shaft Eo of the internalcombustion engine E to integrally rotate therewith via the damper D onanother axial side of the first support wall 4. The damper D is a devicewhich transmits rotation of the internal combustion engine output shaftEo to the input shaft I while damping torsional vibrations of theinternal combustion engine output shaft Eo, and one of various publiclyknown types of dampers can be used. In this embodiment, the damper D isstructured to have plural coil springs arranged along thecircumferential direction, fixed to and integrated with a drive plate DPfixed to the internal combustion engine output shaft Eo, andspline-coupled to the input shaft I. The damper D is formed to have asmaller diameter in its entirety than the drive plate DP, and isarranged on one axial side of the drive plate DR Further, across theinput shaft I and the first support wall 4, a third seal member 63 isdisposed for creating a liquid-tight state therebetween for suppressingleakage of oil to another axial side (the side of the damper D and theinternal combustion engine E).

In this embodiment, in an inner diameter portion on one axial endportion of the input shaft I, a shaft end hole portion 12 extending inthe axial direction is formed. In this shaft end hole portion 12,another axial end portion of the intermediate shaft M is inserted in theaxial direction. Further, the input shaft I integrally has, on its oneaxial end portion, a flange portion 11 extending in the radial directionfrom a body portion (portion extending in the axial direction) of theinput shaft I. The flange portion 11 enters the inside of the clutchcase CH and is coupled to a clutch hub 21 of the clutch CL housed in theclutch case CH. A fourth bearing 54 is disposed on another axial side ofthe flange portion 11, and a third bearing 53 is disposed on a radiallyouter side of the flange portion 11 and on one axial side of the clutchhub 21 provided in the clutch CL.

The intermediate shaft M is a shaft for inputting one or both of torqueof the rotary electrical machine MG and torque of the internalcombustion engine E via the clutch CL to the speed change mechanism TM,and is spline coupled to the clutch case CH. As illustrated in FIG. 2,this intermediate shaft M is disposed in a state of penetrating the oilpump 18. As described above, the through hole in the axial direction isformed in a radially center portion of the pump case 8, and theintermediate shaft M penetrates the oil pump 18 via this through hole.The intermediate shaft M is supported in the radial direction in arotatable state with respect to the oil pump 18. In other words, thepump case 8 of the oil pump 18 rotatably supports the intermediate shaftM which is the input shaft (speed change input shaft) of the speedchange mechanism TM. Further, the other axial end portion of theintermediate shaft M is inserted in the shaft end hole portion 12 of theinput shaft I in the axial direction. At this point, a predetermined gapis formed between an end face on the other axial side of theintermediate shaft M and a face defining a bottom portion in the axialdirection in the shaft end hole portion 12 of the input shaft I. In thisembodiment, the intermediate shaft M has, in its inner diameter portion,plural oil passages including a supply oil passage 15 and a dischargedoil passage 16. The supply oil passage 15 extends in the axial directionon the other axial side of the intermediate shaft M, and extends in theradial direction at a predetermined position in the axial direction andopens in an outer peripheral face of the intermediate shaft M, so as tocommunicate with an operating oil chamber 37 of the clutch CL. Thedischarged oil passage 16 extends in the axial direction on the otheraxial side of the intermediate shaft M at a position different from thesupply oil passage 15 in the circumferential direction, and opens in theend face on the other axial side.

The clutch CL is a friction engagement device which is provided to becapable of switching transmission and disconnection of driving forcebetween the input shaft I and the intermediate shaft M as describedabove, and selectively drive couples the internal combustion engine Eand the rotary electrical machine MG In this embodiment, the clutch CLis structured as a wet multi-plate clutch mechanism which operates in aspace supplied with oil. As illustrated in FIG. 2, the clutch CL isstructured to include the clutch hub 21 as an input side member, aclutch drum 26 as an output side member, plural friction plates 31, anda piston 36.

The clutch hub 21 has a cylindrical portion 22 formed in a cylindricalshape and holding the plural friction plates 31 from a radially innerside, and an annular plate-shaped portion 24 extending on a radiallyinner side from another axial end portion of the cylindrical portion 22.The clutch hub 21 is coupled to the flange portion 11 of the input shaftI so as to integrally rotate with the input shaft I, and is arranged ona radially inner side with respect to the clutch drum 26. As describedabove, the input shaft I is drive-coupled to the internal combustionengine E. Thus, the clutch hub 21 is drive-coupled to the internalcombustion engine E via the input shaft I. The clutch drum 26 is formedin a cylindrical shape and holds the plural friction plates 31 from aradially outer side. The clutch drum 26 is coupled to the intermediateshaft M via the clutch case CH so as to integrally rotate therewith. Asdescribed above, the intermediate shaft M is drive-coupled to the speedchange mechanism TM. Therefore, the clutch drum 26 is drive-coupled tothe speed change mechanism TM via the clutch case CH and theintermediate shaft M. In other words, the intermediate shaft M drivecouples the clutch drum 26 and the speed change mechanism TM. The pluralfriction plates 31 are each held slidably in the axial direction by theclutch hub 21 and the clutch drum 26. On another axial side with respectto the plural friction plates 31, a backing plate 32 functioning as apressing member for engaging the plural friction plates 31 with eachother is held. This backing plate 32 is held in a state of beingrestricted in movement in the axial direction by a snap ring 33. Thepiston 36 is arranged on one axial side with respect to the pluralfriction plates 31 in a state of being biased toward the one axial sideby a return spring.

In this embodiment, the operating oil chamber 37 in a liquid-tight stateis formed between the clutch case CH, which is integrated with theclutch drum 26, and the piston 36. The operating oil chamber 37 is anoil chamber for controlling the engagement state (complete engagement,complete release, or partial engagement therebetween) of the clutch CL.To this operating oil chamber 37, pressure oil discharged by the oilpump 18 and adjusted to a predetermined oil pressure by a hydrauliccontrol device (not-illustrated) is supplied via the supply oil passage15 formed in the intermediate shaft M and a communication oil passage 48formed in the clutch case CH. When the oil pressure in the operating oilchamber 37 increases and becomes larger than biasing force of the returnspring, the piston 36 moves in a direction (another axial side in thisexample) to expand the volume of the operating oil chamber 37, tothereby engage the plural friction plates 31 with each other incooperation with the backing plate 32. As a result, torque of theinternal combustion engine E transmitted from the input shaft I istransmitted to the rotary electrical machine MG and the intermediateshaft M via the clutch CL. On the other hand, a circulation oil chamber38 is formed on the opposite side of the piston 36 from the operatingoil chamber 37. The circulation oil chamber 38 is an oil chamber inwhich oil mainly for cooling the clutch CL circulates. In thiscirculation oil chamber 38, the pressure oil discharged by the oil pump18 and adjusted to a predetermined oil pressure by the hydraulic controldevice (not-illustrated) is supplied via a circulation oil passage 47formed continuously in the axial direction in both the clutch case CHand the pump drive shaft 10. That is, the pump drive shaft 10 internallyincludes the circulation oil passage 47 which is an oil passage forsupplying oil to the clutch CL. In this embodiment, the circulation oilpassage 47 functions as a “supply oil passage” in the present invention.

The clutch case CH is a case for housing the clutch CL, and includes thepump drive shaft 10 extending toward the one axial side and isdrive-coupled to the inner rotor 18 b. The clutch case CH is disposedacross the input shaft I and the intermediate shaft M in a state torelatively rotate with the input shaft I and integrally rotate with theintermediate shaft M. That is, in this embodiment, the clutch case CH isdrive-coupled to the intermediate shaft M out of the input shaft I andthe intermediate shaft M. The clutch case CH then houses the clutch CLso as to surround both sides in the axial direction and a radially outerside of the clutch CL, on a radially outer side of the input shaft I andthe intermediate shaft M which are arranged coaxially. Accordingly, theclutch case CH is structured to have an another-side radially extendingportion 41 arranged on another axial side of the clutch CL to extend inthe radial direction, a one-side radially extending portion 45 arrangedon one axial side of the clutch CL to extend in the radial direction,and a cylindrical axially extending portion 49 arranged on the radiallyouter side of the clutch CL to extend in the axial direction. Theaxially extending portion 49 couples the one-side radially extendingportion 45 and the another-side radially extending portion 41 in theaxial direction at radially outer end portions thereof.

The another-side radially extending portion 41 has a shape extending atleast in the radial direction, and extends in the radial direction andthe circumferential direction in this embodiment. The another-sideradially extending portion 41 sections another axial side of thecirculation oil chamber 38. A through hole in the axial direction isformed in a radially center portion of the another-side radiallyextending portion 41, and the input shaft I inserted through thisthrough hole penetrates the another-side radially extending portion 41and is inserted in the clutch case CH. The another-side radiallyextending portion 41 integrally has, on its radially inner end portion,an axially projecting portion 42 having a cylindrical shape (boss shape)projecting toward the other axial side. The axially projecting portion42 is formed to surround the periphery of the input shaft I. A fifthbearing 55 is disposed between the axially projecting portion 42 and theinput shaft I. Assuming that the portion of the another-side radiallyextending portion 41 excluding the axially projecting portion 42 is abody portion, in this example, the body portion of the another-sideradially extending portion 41 is a member having a shape curving in adish form which protrudes toward the one axial side so that a radiallyinner portion is located entirely on the one axial side with respect toa radially outer portion.

The another-side radially extending portion 41 is arranged adjacent at apredetermined space apart on one axial side with respect to the firstsupport wall 4, with the axially projecting portion 42 being adjacent ata predetermined space apart on a radially inner side with respect to theaxially projecting portion 5 of the first support wall 4. Further, theanother-side radially extending portion 41 is arranged adjacent at apredetermined space apart on another axial side with respect to theclutch hub 21 and the flange portion 11 of the input shaft I. Then,across the axially projecting portion 42 and the axially projectingportion 5 of the first support wall 4, there are disposed a secondbearing 52 and a second seal member 62 which creates a liquid-tightstate between the axially projecting portion 42 and the axiallyprojecting portion 5 for suppressing leakage of oil to the one axialside (the side of the rotary electrical machine MG). That is, the secondbearing 52 supports the another-side radially extending portion 41forming the clutch case CH so as to be relatively rotatable with respectto the case 2, which is a non-rotating member. As illustrated in FIG. 2,the second bearing 52 is disposed in a state of abutting a steppedportion 42 a (a portion in which an outer diameter of the axiallyprojecting portion 42 varies) formed on an outer peripheral face of theaxially projecting portion 42 from the other axial side.

In this embodiment, the second bearing 52 is a bearing (rolling bearing)having an outer wheel, an inner wheel, and rolling elements interveningbetween the outer wheel and the inner wheel. Specifically, the secondbearing 52 is a ball bearing with the rolling elements being balls, andis structured to be capable of receiving both of a radial load and anaxial load. That is, the hybrid drive apparatus 1 according to thisembodiment includes the second bearing 52 supporting the clutch case CHat another axial side in the radial direction and the axial direction onthe case 2. Then, as illustrated in FIG. 2, the second bearing 52 isarranged to overlap with the another-side radially extending portion 41(specifically, a radially outer portion of the another-side radiallyextending portion 41) in the axial direction. In other words, the secondbearing 52 is arranged to overlap with the another-side radiallyextending portion 41 (specifically, the radially outer portion of theanother-side radially extending portion 41) when it is seen from theradial direction. The second bearing 52 may be one at least capable ofsupporting the clutch case CH at the other axial side in the radialdirection, and may be a bearing other than the ball bearing. Forexample, the second bearing 52 may be a roller bearing with the rollingelements being rollers. Note that in this specification, to “overlap” ina certain direction regarding the arrangement of two members means thatthe two members have, at least partially, portions at the same positionwith respect to the arrangement in this direction.

The axially extending portion 49 has a cylindrical shape surrounding theradially outer side of the clutch CL, and extends from the radiallyouter end portion of the another-side radially extending portion 41toward the one axial side in this embodiment. The axially extendingportion 49 sections a radially outer side of the circulation oil chamber38. In this example, the axially extending portion 49 is formedintegrally with the another-side radially extending portion 41. Further,in this embodiment, the axially extending portion 49 is arranged on aradially outer side of the clutch drum 26 and at a predetermined spaceapart from the clutch drum 26. That is, the axially extending portion 49is arranged so that an inner peripheral face of the axially extendingportion 49 and an outer peripheral face of the clutch drum 26 face eachother at a predetermined space apart in the radial direction.

Further, as illustrated in FIG. 2, the axially extending portion 49 isformed in a stepped shape to proceed step-wise to the radially outerside in its entirety as this portion proceeds to the one axial side.Then, an outer peripheral face of a portion located on another axialside in the axially extending portion 49 is a first abutting portion 49a abutting and supporting an inner peripheral face of the rotor Ro ofthe rotary electrical machine MG from a radially inner side. That is, inthis example, the rotor Ro of the rotary electrical machine MG issupported by the clutch case CH. Further, an inner peripheral face of aportion located on one axial side with respect to the first abuttingportion 49 a in the axially extending portion 49 is a second abuttingportion 49 b abutting an outer peripheral face of the one-side radiallyextending portion 45. Note that in this embodiment, the second abuttingportion 49 b is located on a radially outer side with respect to thefirst abutting portion 49 a.

The one-side radially extending portion 45 has a shape extending atleast in the radial direction, and extends in the radial direction andthe circumferential direction in this embodiment. The one-side radiallyextending portion 45 sections one axial side of the circulation oilchamber 38 in a radially inner portion with respect to the piston 36 anda radially outer portion with respect to the operating oil chamber 37.In a radially center portion of the one-side radially extending portion45, a through hole in the axial direction is formed, and theintermediate shaft M inserted through this through hole penetrates theone-side radially extending portion 45 and is inserted in the clutchcase CH. The one-side radially extending portion 45 integrally has, inits radially inner end portion, an axially projecting portion 46 havinga cylindrical shape (boss shape) projecting toward the one axial side.The axially projecting portion 46 is formed to surround the periphery ofthe intermediate shaft M. The one-side radially extending portion 45(axially projecting portion 46) has its inner peripheral face of theradially inner end portion abutting the outer peripheral face of theintermediate shaft M across the entire circumferential direction.Assuming that the portion of the one-side radially extending portion 45excluding the axially projecting portion 46 is a body portion, in thisexample, the body portion of the one-side radially extending portion 45is a plate-shaped member having a shape in which a radially innerportion is offset entirely on another axial side from a radially outerportion so that the radially inner portion is located on another axialside with respect to the radially outer portion.

On the radially inner end portion of the one-side radially extendingportion 45, the pump drive shaft 10 which extends toward the one axialside and is drive-coupled to the inner rotor 18 b is provided. In thisexample, as illustrated in FIG. 2, the pump drive shaft 10 is formedintegrally with the one-side radially extending portion 45, andspecifically, another axial end portion of the pump drive shaft 10 andone axial end portion of the axially projecting portion 46 are coupledintegrally. Then, the pump drive shaft 10 is spline-coupled to theintermediate shaft M so as to integrally rotate therewith. Note that asillustrated in FIG. 2, an outer diameter of the axially projectingportion 46 is larger than an outer diameter of the pump drive shaft 10.Accordingly, in a coupling portion as a boundary between the axiallyprojecting portion 46 and the pump drive shaft 10, an annular faceformed by one axial end face of the axially projecting portion 46 and acylindrical face formed by the outer peripheral face of the pump driveshaft 10 are formed in a positional relation of being orthogonal to eachother, which makes it possible to properly fix the first bearing 51 asdescribed later.

The one-side radially extending portion 45 is arranged adjacent at apredetermined space apart on another axial side with respect to thesecond support wall 7 and the oil pump 18 (pump body 90), with theaxially projecting portion 46 and the pump drive shaft 10 being adjacentat a predetermined space apart on a radially inner side with respect tothe axially projecting portion 90 b provided on the pump body 90.Moreover, the one-side radially extending portion 45 has its radiallyinner portion arranged adjacent at a predetermined space apart on oneaxial side with respect to the clutch hub 21 and the flange portion 11of the input shaft I. Then, the first bearing 51 is disposed across thepump drive shaft 10 and the axially projecting portion 90 b of the pumpbody 90, and a first seal member 61 is disposed across the axiallyprojecting portion 46 and the axially projecting portion 90 b of thepump body 90 to create a liquid-tight state therebetween for suppressingleakage of oil to the other axial side (the side of the rotaryelectrical machine MG). That is, the pump drive shaft 10 is supported onthe pump body 90 (pump case 8) via the first bearing 51. Note that thepump case 8 is fixed to the case 2 as described above. Thus, the pumpdrive shaft 10 is supported on the case 2 via the first bearing 51 andthe pump case 8. The first bearing 51 is disposed in a state of, asillustrated in FIG. 2, abutting the one axial end face of the axiallyprojecting portion 46 from the one axial side.

Note that the pump drive shaft 10 is formed integrally with the one-sideradially extending portion 45 forming the clutch case CH as describedabove, it can be said that the one-side radially extending portion 45 issupported on the pump body 90 (pump case 8) via the first bearing 51.That is, the first bearing 51 supports the one-side radially extendingportion 45 forming the clutch case CH so as to be relatively rotatablewith respect to the pump case 8, which is a non-rotating member, and thecase 2 to which the pump case 8 is fixed.

In this embodiment, the first bearing 51 is a bearing (rolling bearing)having an outer wheel 51 a, an inner wheel 51 b, and rolling elements 51c intervening between the outer wheel 51 a and the inner wheel 51 b (seeFIG. 3). Specifically, the first bearing 51 is a ball bearing with therolling elements being balls, and is structured to be capable ofreceiving both of a radial load and an axial load. That is, the hybriddrive apparatus 1 according to this embodiment includes the firstbearing 51 supporting the clutch case CH at one axial side in the radialdirection and the axial direction on the case 2. As described above, inthis example, the clutch case CH is supported in the radial directionand the axial direction on the case 2 at both sides in the axialdirection by the first bearing 51 and the second bearing 52. Then, boththe first bearing 51 and the second bearing 52 are a rolling bearing(ball bearing in this example) having an outer wheel, an inner wheel,and rolling elements. Thus, in this structure, it is possible to supportthe clutch case CH precisely in the radial direction, and it is easy tosuppress displacement in the radial direction of the outer peripheralface of the pump drive shaft 10 provided in the clutch case CH within arelatively narrow range.

Note that the outer wheel 51 a of the first bearing 51 is fitted with aninner peripheral face of the axially projecting portion 90 b (aninterference fit by press fitting in this example) to be fixed inposition in the radial direction, and the inner wheel 51 b is fittedwith the outer peripheral face of the pump drive shaft 10 (aninterference fit with a smaller interference compared to the fitting ofthe outer wheel 51 a or a free running fit in this example) to be fixedin position in the radial direction. Further, as illustrated in FIG. 2,the first bearing 51 is arranged to overlap with the one-side radiallyextending portion 45 (specifically, the radially outer portion of theone-side radially extending portion 45) in the axial direction. In otherwords, the first bearing 51 is arranged to overlap with the one-sideradially extending portion 45 (specifically, the radially outer portionof the one-side radially extending portion 45) when it is seen from theradial direction. The first bearing 51 may be one at least capable ofsupporting the clutch case CH at the one axial side in the radialdirection, and may be a bearing other than the ball bearing. Forexample, the first bearing 51 may be a roller bearing with the rollingelements being rollers.

Further, the one-side radially extending portion 45 is coupled to aportion of one axial side of the axially extending portion 49 in thevicinity of the radially outer end portion. Specifically, as illustratedin FIG. 2, the one-side radially extending portion 45 is joined theretoby welding in a state of being fitted (an interference fit by pressfitting in this example) with the second abutting portion 49 b of theaxially extending portion 49. That is, the one-side radially extendingportion 45 and the axially extending portion 49 are joined by weldingand integrated. Note that the welding is performed from one axial sideon an abutting part of the inner peripheral face of the axiallyextending portion 49 (second abutting portion 49 b) and the outerperipheral face of the one-side radially extending portion 45, and thusa joining part 85 by welding is formed around the same radial positionas the second abutting portion 49 b. As described above, the secondabutting portion 49 b is located on the radially outer side with respectto the first abutting portion 49 a abutting and supporting the innerperipheral face of the rotor Ro from the radially inner side. Thus, thejoining part 85 is located on a radially outer side with respect to theinner peripheral face of the rotor Ro. Accordingly, the joining part 85by welding can be at a position apart in the radial direction from thepump drive shaft 10, thereby suppressing deformation of the pump driveshaft 10 and the one-side radially extending portion 45, on which thepump drive shaft 10 is provided on the radially inner end portion, byheat during the welding.

Moreover, in this embodiment, as illustrated in FIG. 2, the radiallyouter portion of the one-side radially extending portion 45 and oneaxial side portion of the axially extending portion 49 are joined bywelding in a state that both of faces facing each other in the radialdirection and faces facing each other in the axial direction abut eachother. Accordingly, heat during the welding is suppressed from beingtransmitted intensively to one member of the one-side radially extendingportion 45 and the axially extending portion 49, and temperatures of theone-side radially extending portion 45 and the axially extending portion49 are suppressed from increasing excessively and causing deformation.Note that the heat capacity of the axially extending portion 49 isfavorably formed larger than the heat capacity of the one-side radiallyextending portion 45 because a large quantity of heat during the weldingcan escape to the axially extending portion 49.

Note that in this embodiment, the clutch drum 26 is formed integrallywith this one-side radially extending portion 45. More specifically, inthe vicinity of the radially outer end portion of the one-side radiallyextending portion 45, the cylindrical clutch drum 26 is integrallyformed to extend from the one-side radially extending portion 45 towardthe other axial side. Further, in this embodiment, the operating oilchamber 37 is formed between the radially inner portion of the one-sideradially extending portion 45 and the piston 36. Moreover, in theone-side radially extending portion 45, the communication oil passage 48extending in the radial direction in its entirety while slightlyinclining toward the other axial side with respect to the radialdirection, so as to communicate the supply oil passage 15 with theoperating oil chamber 37, is formed in the axially projecting portion46.

In the space formed in the clutch case CH, the space occupying a majorpart excluding the operating oil chamber 37 is the previously describedcirculation oil chamber 38. Then, in this embodiment, oil discharged bythe oil pump 18 and adjusted to a predetermined oil pressure is suppliedto the circulation oil chamber 38 via the circulation oil passage 47formed to extend in the pump drive shaft 10 and the axially projectingportion 46 in the axial direction. In this embodiment, the fifth bearing55 disposed between the axially projecting portion 42 formed in theanother-side radially extending portion 41 and the input shaft I is abearing with a seal function (here, a needle bearing with sealing)structured to be capable of ensuring a certain degree ofliquid-tightness. Moreover, the one-side radially extending portion 45(axially projecting portion 46) has its inner peripheral face of theradially inner end portion abutting the outer peripheral face of theintermediate shaft M across the entire circumferential direction.Accordingly, by supplying oil to the circulation oil chamber 38 via thecirculation oil passage 47, the circulation oil chamber 38 in the clutchcase CH is basically in a state of being constantly filled with the oil.

Note that although basically the state of being constantly filled withoil is maintained, the oil flows in the circulation oil chamber 38. Thisflow is shown with dashed arrows in FIG. 2. That is, the oil suppliedfrom the circulation oil passage 47 to the circulation oil chamber 38first flows between the one-side radially extending portion 45 and theflange portion 11 and between the piston 36 and the clutch hub 21 towardthe radially outer side, so as to cool the plural friction plates 31.Then, the oil which cooled the plural friction plates 31 flows betweenthe clutch hub 21 and the flange portion 11 and the another-sideradially extending portion 41 toward a radially inner side, and reachesa base end portion of the flange portion 11. Thereafter, the oil isdischarged from the circulation oil chamber 38. Thus, in the hybriddrive apparatus 1 according to this embodiment, it is possible toeffectively cool the plural friction plates 31 provided in the clutch CLwith the large amount of oil which is filled constantly in thecirculation oil chamber 38.

Moreover, although detailed descriptions are omitted, in thisembodiment, in order to efficiently introduce oil supplied from aradially inner side to gaps between the friction plates 31, a throughhole 23 (slit-shaped through hole in this example) penetrating in theradial direction is formed in the cylindrical portion 22 of the clutchhub 21. Further, in order to properly discharge the oil introduced tothe gaps between the friction plates 31 from these gaps, a through hole27 (slit-shaped through hole in this example) penetrating in the radialdirection is formed in the clutch drum 26. Accordingly, the oil suppliedfrom the radially inner side is introduced efficiently to the gapsbetween the friction plates 31, and thereby it is possible to improvethe cooling efficiency of the plural friction plates 31. Note that it isof course possible that the oil may flow in the circumferentialdirection at the same time, but the main flow of the oil is as describedabove.

As illustrated in FIG. 2, in this example, a discharge route of oil fromthe circulation oil chamber 38 is separated into two systems. A firstdischarge route is via a communication hole in the radial directionopening in the outer peripheral face of the input shaft I and thedischarged oil passage 16 formed in the inner diameter portion of theintermediate shaft M. In this embodiment, the outer diameter of theother axial end portion of the intermediate shaft M is formed to beslightly smaller than the inner diameter of the shaft end hole portion12 of the input shaft I, and a predetermined gap is formed between anend face on the other axial side of the intermediate shaft M and a facedefining a bottom portion in the axial direction in the shaft endportion 12 of the input shaft I. Accordingly, the oil discharged fromthe circulation oil chamber 38 via the through hole in the radialdirection formed in the input shaft I can be properly guided to thedischarged oil passage 16 via the gap in the radial direction and thegap in the axial direction formed between the intermediate shaft M andthe shaft end hole portion 12 of the input shaft I. A second dischargeroute is targeted at oil leaking in the axial direction from the fifthbearing 55, and is via the discharged oil passage 72 in the oil passageforming member 71 attached to the first support wall 4. Such a seconddischarge route is defined by the third seal member 63 disposed betweenthe input shaft I and the first support wall 4 and the second sealmember 62 disposed between the axially projecting portion 42 of theclutch case CH and the axially projecting portion 5 of the first supportwall 4. Thus, the oil leaking in the axial direction from the fifthbearing 55 can be guided properly to the discharged oil passage 72.

As illustrated in FIG. 2, the rotary electrical machine MG is arrangedcoaxially with the intermediate shaft M on a radially outer side of theclutch case CH. The rotary electrical machine MG has the stator St fixedto the case 2 and the rotor Ro supported rotatably on a radially innerside of the stator St. That is, the rotary electrical machine MG has therotor Ro on the radially inner side with respect to the stator St. Thestator St has a stator core formed as a stacked structure, in whichplural electromagnetic steel sheets having an annular plate shape arestacked, and fixed on the first support wall 4, and a coil wound on thestator core. Note that in the coil, portions projecting in both sides inthe axial direction of the stator core are coil end portions Ce. Therotor Ro of the rotary electrical machine MG has a rotor core formed asa stacked structure, in which plural electromagnetic steel sheets havingan annular plate shape are stacked, and a permanent magnet embedded inthe rotor core.

In this embodiment, the rotary electrical machine MG is arrangedcoaxially with the clutch case CH to overlap with the clutch case CH inthe axial direction. That is, the rotary electrical machine MG isarranged to overlap with the clutch case CH when it is seen from theradial direction. In this example, particularly the rotor Ro of therotary electrical machine MG is fixed to an outer peripheral portion ofthe axially extending portion 49 forming the clutch case CH.Specifically, the rotor Ro of the rotary electrical machine MG is fixedto the above-described first abutting portion 49 a provided on theaxially extending portion 49. That is, respective inner peripheral facesof the plural electromagnetic steel plates forming the rotor core of therotor Ro are fixed in a state of contacting the outer peripheral face(first abutting portion 49 a) of the axially extending portion 49.Accordingly, the clutch case CH also functions as a rotor support membersupporting the rotor Ro, and in this embodiment, the clutch case CH andthe rotor support member are formed in common. Note that as describedabove, the clutch case CH is supported in the radial direction and theaxial direction on the case 2 at both sides in the axial direction bythe first bearing 51 and the second bearing 52. Moreover, both the firstbearing 51 and the second bearing 52 are a rolling bearing (ball bearingin this example) having an outer wheel, an inner wheel, and rollingelements. Accordingly, it is possible to support the rotor Ro of therotary electrical machine MG with high precision. Then, as describedabove, the clutch drum 26 is thus formed integrally with the clutch caseCH which integrally rotates with the rotor Ro of the rotary electricalmachine MG That is, the rotary electrical machine MG is drive-coupled tothe clutch drum 26 which is an output side member of the clutch CL viathe clutch case CH.

Further, in this embodiment, the damper D is arranged at a predeterminedspace apart on the other axial side of the first support wall 4. Thedamper D is arranged in a space, which retreats toward the one axialside when it is seen from the other axial side, of the first supportwall 4 formed to have a shape curving in a dish form which protrudestoward the one axial side. In this example, moreover, the damper D isarranged in a radially inner side of the coil end portion Ce of anotheraxial side (the side of the internal combustion engine E) of the statorSt of the rotary electrical machine MG to overlap with the coil endportion Ce in the axial direction. That is, the damper D is arranged tooverlap with the coil end portion Ce when it is seen from the radialdirection.

Then, the resolver 19 (one example of a rotation sensor) which is asensor for detecting the rotation angle (rotation phase) of the rotor Rowith respect to the stator St of the rotary electrical machine MG isarranged in the case 2. In this embodiment, as illustrated in FIG. 2,the resolver 19 is arranged adjacent to both the second support wall 7of the case 2 and the one-side radially extending portion 45 on oneaxial side of the clutch case CH. In this example, the resolver 19 is anouter rotor type resolver having a sensor stator on a radially innerside with respect to a sensor rotor. Then, the sensor stator of theresolver 19 is fixed to the cylindrical portion 7 a provided in thesecond support wall 7, and the sensor rotor of the resolver 19 is fixedto an inner peripheral face of one axial end portion of the axiallyextending portion 49.

3. Leakage Suppressing Structure for Oil from the Pump Chamber

As described above, the first bearing 51 supporting the clutch case CHat one axial side in the radial direction (the radial direction and theaxial direction in this example) is supplied with oil leaking to anotheraxial side through the space between the pump body 90 and the pump driveshaft 10 from the pump chamber 18 a. In the present invention, it ispossible to limit the amount of oil leaking from the pump chamber 18 ato the other axial side without arranging a dedicated member (sealmember or the like) for limiting leakage of oil. Here, a leakagesuppressing structure for oil from the pump chamber 18 a according tothis embodiment will be described in detail based on FIG. 3.

As illustrated in FIG. 3, the pump case 8 (pump body 90 in this example)includes a partition wall 90 a partitioning the first bearing 51 and theinner rotor 18 b. That is, another axial side of the pump chamber 18 ais sectioned by the partition wall 90 a.

Further, one axial side of the pump chamber 18 a is sectioned by asection wall 91 a provided in the pump case 8 (pump cover 91 in thisexample). The section wall 91 a is arranged on the opposite of the innerrotor 18 b from the partition wall 90 a in the axial direction. Thepartition wall 90 a includes a drive shaft insertion hole 90 c throughwhich the pump drive shaft 10 is inserted. Here, a diameter of an innerperipheral face of the drive shaft insertion hole 90 c is “Φc”. Then, agap between the outer peripheral face of the pump drive shaft 10 and theinner peripheral face of the drive shaft insertion hole 90 c isdesignated as a distribution passage L for oil flowing from the pumpchamber 18 a to the first bearing 51. That is, the distribution passageL is a flow passage of oil leaking from the pump chamber 18 a to theother axial side along the outer peripheral face of the pump drive shaft10.

In this embodiment, as illustrated in FIG. 3, the pump drive shaft 10 isformed in a stepped shape with one axial side being a small diameterportion 10 a and another axial side being a large diameter portion 10 b,so as to reduce a dragging distance when the first bearing 51 isassembled with the pump drive shaft 10 from the one axial side. Here, adiameter of an outer peripheral face of the small diameter portion 10 ais “Φa”, and a diameter of an outer peripheral face of the largediameter portion 10 b is “Φb”. In one axial end portion of the smalldiameter portion 10 a, the key grooves 10 d are formed, which engagewith the keys 18 d provided on the inner rotor 18 b. Then, the pumpdrive shaft 10 is arranged so that an inner peripheral face of the driveshaft insertion hole 90 c faces the outer peripheral face of the smalldiameter portion 10 a. Further, the first bearing 51 is arranged incontact with the outer peripheral face of the large diameter portion 10b.

Now, to allow rotation of the inner rotor 18 b and the outer rotor 18 cin the pump chamber 18 a, axial widths of the inner rotor 18 b and theouter rotor 18 c are set slightly smaller than an axial width of thepump chamber 18 a. Thus, as illustrated in FIG. 3, gaps exist betweenthe inner rotor 18 b and the outer rotor 18 c and the walls sectioningthe pump chamber 18 a (the partition wall 90 a and the section wall 91a). Accordingly, not all of the oil increased in pressure in the pumpchamber 18 a is discharged via the discharge chamber (not-illustrated),and part thereof flows through these gaps to a lower pressure part inthe pump chamber 18 a. That is, such gaps form pump flow passages, whichare flow passages of oil in the pump chamber 18 a.

Here, a pump flow passage formed by the gap between the partition wall90 a and the inner rotor 18 b is designated as a first pump flow passageL1. Further, a pump flow passage formed by the gap between the sectionwall 91 a and the inner rotor 18 b is designated as a second pump flowpassage L2. As illustrated in FIG. 3, the first pump flow passage L1 hasan axial width “δ” and communicates at its radially inner end portionwith the distribution passage L. Note that in this embodiment, the firstpump flow passage L1 also communicates with a space formed on a radiallyinner side with respect to the inner peripheral face of the inner rotor18 b (hereinafter referred to as a “target space”). This target space isa low pressure space relative to the first pump flow passage L1 locatedat a position closer to a discharge port (discharge chamber) which isnot shown, and thus as illustrated in FIG. 3 a distribution route of oilfrom the first pump flow passage L1 toward the distribution passage Lvia the target space is formed. In this embodiment, the first pump flowpassage L1 functions as an “pump flow passage” in the present invention.

Further, the second pump flow passage L2 communicates with a spaceformed in one axial side of the pump drive shaft 10 (space denoted by asymbol L3 in FIG. 3). This space is formed in an annular shape and, asillustrated in FIG. 2, communicates with the circulation oil passage 47.That is, this space is a communication passage L3 communicating thesecond pump flow passage L2 with the circulation oil passage 47. Inother words, the second pump flow passage L2 communicates with thecirculation oil passage 47 via the communication passage L3. Note thatthe communication passage L3 is a low pressure space relative to thesecond pump flow passage L2 located at a position closer to thedischarge port (discharge chamber) which is not shown, and thus asillustrated in FIG. 3, a distribution route of oil from the second pumpflow passage L2 toward the communication passage L3 and a distributionroute of oil from the communication passage L3 toward the circulationoil passage 47 (see FIG. 2) are formed. Thus, the circulation oilpassage 47 is basically supplied with the pressure oil discharged by theoil pump 18 and adjusted to a predetermined pressure by the hydrauliccontrol device (not-illustrated), and is structured to be supplied alsowith the oil leaking from the pump chamber 18 a. In this embodiment, thesecond pump flow passage L2 functions as a “section wall side pump flowpassage” in the present invention.

Note that the axial widths of the first pump flow passage L1 and thesecond pump flow passage L2 change according to the axial position ofthe inner rotor 18 b in the pump chamber 18 a. Then, the inner rotor 18b may be at a position displaced on an axially outer side from the axialcenter position of the pump chamber 18 a depending on the structures ofthe suction chamber 92 and the discharge chamber (not-illustrated), butin a stationary state, it is located at a position close to the axialcenter position of the pump chamber 18 a. Thus, the axial width of thesecond pump flow passage L2 is a value which is the same as or close tothe axial width δ of the first pump flow passage L1.

Then, a distribution passage diameter difference, which is a differencebetween the diameter of the outer peripheral face of the pump driveshaft 10 and the diameter of the inner peripheral face of the driveshaft insertion hole 90 c in the distribution passage L, is set so thatthe distribution passage L functions as a narrowed portion which limitsa flow rate of oil. Note that in this embodiment, since the smalldiameter portion 10 a of the pump drive shaft 10 faces the innerperipheral face Of the drive shaft insertion hole 90 c, the outerperipheral face of the pump drive shaft 10 in the distribution passage Lis the outer peripheral face of the small diameter portion 10 a. Thus,in this embodiment, the distribution passage diameter difference is“Φc-Φa”.

Specifically, a difference between the diameter of the large diameterportion 10 b of the pump drive shaft 10 and the diameter of the smalldiameter portion 10 a is designated as a pump shaft step width, and thedistribution passage diameter difference can be set to a value smallerthan the pump shaft step width. For example, the distribution passagediameter difference can be set to a value which is one-half orone-fourth of the pump shaft step width. Note that the pump shaft stepwidth is represented as “Φb-Φa”, and thus “Φc-Φa” (distribution passagediameter difference) is set smaller than “Φb- Φa” (pump shaft stepwidth). That is, the distribution passage diameter difference is set soas to satisfy the relation of “Φb>Φc>Φa”.

Moreover, in this embodiment, the distribution passage diameterdifference is set so that a flow passage sectional area of thedistribution passage L is smaller than a flow passage sectional area ofthe first pump flow passage L1. For example, the flow passage sectionalarea of the distribution passage L can be set to a value which isone-half or one-fourth of the flow passage sectional area of the firstpump flow passage L1. Here, as illustrated in FIG. 3, when a diameter ofan inner peripheral face of another axial side portion with respect tothe key 18 d in the inner rotor 18 b is “Φd”, the flow passage sectionalarea of the first pump flow passage L1 can be regarded in a simplifiedmanner as the area “π×Φd×δ” of a cylinder face whose diameter is “Φd”and axial width is “δ”. Further, the flow passage sectional area of thedistribution passage L can be regarded in a simplified manner as anaxial center orthogonal cross-sectional area “π×Φc×Φc/4−π×Φa×Φa/4” of acylinder whose inner diameter is “Φa” and outer diameter is “Φc”. Thus,in this example, the distribution passage diameter difference is set sothat “π×Φc×Φc/4−π×Φa×Φa/4” is smaller than “π×Φd×δ”. By thus setting theflow passage sectional area of the distribution passage L smaller thanthe flow passage sectional area of the first pump flow passage L1, thedistribution passage L functions properly as the narrowed portion, andin this structure it is possible to guide into the distribution passageL only part of oil which is not discharged from the discharge chamberbut flows through the first pump flow passage L1. That is, the amount ofoil leaking in the axial direction along the outer peripheral face ofthe pump drive shaft 10 from the pump chamber 18 a can be limited, andthe amount of oil discharged via the discharge chamber (not-illustrated)from the pump chamber 18 a can be secured properly.

Note that as described above, on the opposite side of the inner rotor 18b from the first pump flow passage L1 in the axial direction, the secondpump flow passage L2 is formed. Then, the first pump flow passage L1 andthe second pump flow passage L2 communicate with each other via a gapbetween outer teeth of the inner rotor 18 b and inner teeth of the outerrotor 18 c. Further, the above-described target space and thecommunication passage L3 communicate with each other via gaps betweenthe inner rotor 18 b and the pump drive shaft 10 (such as a gap betweenthe keys 18 d and the key grooves 10 d). Accordingly, when oil which isnot discharged to the distribution passage L due to that thedistribution passage L functions as the narrowed portion flows to thecommunication passage L3 via the second pump flow passage L2 and theabove-described gap, and is supplied to the circulation oil passage 47.Thus, in this structure, the oil which is not discharged to thedistribution passage L due to that the distribution passage L functionsas the narrowed portion can be actively guided to the circulation oilpassage 47 for supplying oil to the clutch CL.

Further, the distribution passage diameter difference (Φc-Φa) is setlarger than a maximum value of an allowance of displacement in theradial direction of the pump drive shaft 10 supported by the firstbearing 51. For example, the distribution passage diameter differencecan be set to substantially the same value as this maximum value, or canbe set to the value which is double the maximum value. Thus, a contactbetween the outer peripheral face of the pump drive shaft 10 and theinner peripheral face of the drive shaft insertion hole 90 c issuppressed. Note that the displacement amount (sway amount) in theradial direction of the pump drive shaft 10 is decided according to atleast a radial gap of the first bearing 51 in a state of being fixedbetween the large diameter portion 10 b of the pump drive shaft 10 andthe axially projecting portion 90 b of the pump body 90. Note that theradial gap of the first bearing 51 is a relative displacement amount inthe radial direction between the outer wheel 51 a and the inner wheel 51b allowed by a clearance existing in the first bearing 51.

Further, the displacement amount in the radial direction of the pumpdrive shaft 10 also depends on an allowance of displacement in theradial direction of the first bearing 51 itself. For example,displacement in the radial direction of the first bearing 51 itself isallowed by a gap between an outer peripheral face of the outer wheel 51a of the first bearing 51 and the inner peripheral face of the axiallyprojecting portion 90 b fitting with and supporting this outer wheel 51a as well as a gap between an inner peripheral face of the inner wheel51 b of the first bearing 51 and the outer peripheral face of the largediameter portion 10 b fitting with and supporting this inner wheel 51 b.Note that the degrees of these respective factors, which are factors ofdisplacement in the radial direction of the pump drive shaft 10, aredecided according to dimensional tolerances and attaching positiontolerances of respective members, and the like.

Note that in this embodiment, as described above, the clutch case CH issupported in the radial direction and the axial direction on the case 2at both sides in the axial direction by the first bearing 51 and thesecond bearing 52. Then, both the first bearing 51 and the secondbearing 52 are a rolling bearing (a ball bearing in this example) havingan outer wheel, an inner wheel, and rolling elements. Thus, in thisstructure, it is possible to precisely support the clutch case CH in theradial direction, and it is easy to suppress the maximum value of theallowance of displacement in the radial direction of the pump driveshaft 10 supported by the first bearing 51, which is an amount fordetermining a lower limit value of the distribution passage diameterdifference, to a low value of a degree which is decided by theabove-described factors. That is, in this structure, while suppressing acontact between the outer peripheral face of the pump drive shaft 10 andthe inner peripheral face of the drive shaft insertion hole 90 c, it iseasy to set the distribution passage diameter difference to a minimalvalue so that the distribution passage L functions properly as thenarrowed portion.

4. Other Embodiments

At last, other embodiments of the hybrid drive apparatus according tothe present invention will be described. Note that characteristicstructures disclosed in each of the following embodiments are not onlyapplied in the embodiment, but may also be applied in combination withcharacteristic structures disclosed in the other embodiments as long asno inconsistency occurs.

-   (1) In the above-described embodiment, the case where the    distribution passage diameter difference is set to a value smaller    than the pump shaft step width, and the flow passage sectional area    of the distribution passage L is set smaller than the flow passage    sectional area of the first pump flow passage L1, is described as an    example. However, the embodiment of the present invention is not    limited to this, and it is possible to change the distribution    passage diameter difference appropriately according to the amount of    oil needed for lubricating the first bearing 51, and the like. For    example, it is possible to set the distribution passage diameter    difference to a value smaller than the pump shaft step width, and    set the distribution passage diameter difference so that the flow    passage sectional area of the distribution passage L is larger than    the flow passage sectional area of the first pump flow passage L1.    Further, it is possible to set the distribution passage diameter    difference to a value larger than the pump shaft step width, and set    the distribution passage diameter difference so that the flow    passage sectional area of the distribution passage L is smaller than    the flow passage sectional area of the first pump flow passage L1.    Moreover, it is possible to set the distribution passage diameter    difference to a value larger than the pump shaft step width, and set    the distribution passage diameter difference so that the flow    passage sectional area of the distribution passage L is larger than    the flow passage sectional area of the first pump flow passage L1.-   (2) In the above-described embodiment, the case where the    distribution passage diameter difference is set larger than the    maximum value of the allowance of displacement in the radial    direction of the pump drive shaft 10 supported by the first bearing    51 is described as an example. However, the embodiment of the    present invention is not limited to this, and the distribution    passage diameter difference can be changed appropriately according    to the amount of oil needed for lubricating the first bearing 51, a    tendency of the radial position of the pump drive shaft 10 when the    hybrid drive apparatus 1 is in use, and the like. For example, it is    also possible to set the distribution passage diameter difference    smaller than the maximum value of the allowance of displacement in    the radial direction of the pump drive shaft 10 supported by the    first bearing 51. For example, the distribution passage diameter    difference can be set to a value which is one-half or one-fourth of    the maximum value of the allowance of displacement in the radial    direction of the pump drive shaft 10 supported by the first bearing    51.-   (3) In the above-described embodiment, the case where the pump drive    shaft 10 is formed in a stepped shape, with one axial side being the    small diameter portion 10 a and another axial side being the large    diameter portion 10 b, is described as an example. However, the    embodiment of the present invention is not limited to this, and it    is possible to have a structure such that the pump drive shaft 10 is    formed to have the size of an outer diameter which is even in the    axial direction. In this case, a portion of the pump drive shaft 10    abutting the first bearing 51 from the radially inner side and a    portion of the pump drive shaft 10 defining a radially inner side of    the distribution passage L are located at the same radial position.-   (4) In the above-described embodiment, the case where basically the    circulation oil chamber 38, which is a space occupying the major    part excluding the operating oil chamber 37 in the space formed    inside the clutch case CH, is constantly in a state of being filled    with oil is described as an example. However, the embodiment of the    present invention is not limited to this, and in another preferred    embodiment of the present invention, the space excluding the    operating oil chamber 37 in the clutch case CH is structured as a    space which is supplied with oil but not necessarily filled with the    oil. In this case, the space excluding the operating oil chamber 37    in the clutch case CH is need not necessarily be sectioned in an    oil-tight state.-   (5) In the above-described embodiment, the case where the second    pump flow passage L2 communicates with the circulation oil passage    47 is described as an example. However, the embodiment of the    present invention is not limited to this, and it is possible to have    a structure such that the second pump flow passage L2 communicates    with an oil passage other than the circulation oil passage 47, or a    structure such that the second pump flow passage L2 does not    communicate with the circulation oil passage 47 but is sealed or    discharged to a drain.-   (6) In the above-described embodiment, the case where the joining    part 85 by welding is located on the radially outer side with    respect to the inner peripheral face of the rotor Ro is described as    an example. However, the embodiment of the present invention is not    limited to this, and it is possible to have a structure such that    the joining part 85 is located on a radially inner side with respect    to the inner peripheral face of the rotor Ro. Further, in the    above-described embodiment, the case where the one-side radially    extending portion 45 and the axially extending portion 49 are joined    by welding and integrated is described as an example, but it is    possible to have a structure such that the one-side radially    extending portion 45 and the axially extending portion 49 are    integrated by a fixing method other than welding (fixing by    fastening with fastening members, fixing with a caulking structure,    or the like).-   (7) In the above-described embodiment, the case where the clutch    case CH is drive-coupled to the intermediate shaft M out of the    input shaft I and the intermediate shaft M is described as an    example, but it is possible to have a structure such that the clutch    case CH is drive-coupled to the input shaft I out of the input shaft    I and the intermediate shaft M. In this case, the clutch drum 26    which integrally rotates with the clutch case CH is the input side    member of the clutch CL, and the clutch hub 21 drive-coupled to the    intermediate shaft M is the output side member of the clutch CL.-   (8) In the above-described embodiment, the case where the oil pump    18 is an inscribed type gear pump is described as an example.    However, the embodiment of the present invention is not limited to    this, and the oil pump 18 may be an oil pump of a structure other    than the inscribed type gear pump, such as a circumscribed type gear    pump or a vane pump. Also in these cases, it can be structured such    that a rotor is arranged coaxially with the intermediate shaft M in    a pump chamber of the oil pump, and this rotor is the “pump rotor”    in the present invention.-   (9) In the above-described embodiment, the case where the rotor Ro    of the rotary electrical machine MG is fixed in contact with the    outer peripheral face of the axially extending portion 49 is    described as an example, but it is possible to have a structure such    that the rotor Ro of the rotary electrical machine MG is supported    by any other member forming the clutch case CH (namely, the one-side    radially extending portion 45 or the another-side radially extending    portion 41).-   (10) Regarding other structures, the embodiment disclosed in this    specification is an example in all respects, and the embodiment of    the present invention is not limited thereto. That is, as long as    the structures described in the claims of the present application    and structures equivalent thereto are included, a structure in which    part of the structure which is not described in the claims is    appropriately changed belongs of course to the technical scope of    the present invention.

The present invention can be preferably used for a hybrid driveapparatus including a first shaft drive-coupled to an internalcombustion engine, a second shaft drive-coupled to a speed changemechanism, a clutch drive-coupled selectively to the first shaft and thesecond shaft, a rotary electrical machine, and a case housing the clutchand the rotary electrical machine.

1. A hybrid drive apparatus, comprising: a first shaft drive-coupled toan internal combustion engine; a second shaft drive-coupled to a speedchange mechanism; a clutch drive-coupled selectively to the first shaftand the second shaft; a rotary electrical machine; a case housing theclutch and the rotary electrical machine; a clutch case drive-coupled toone of the first shaft and the second shaft and housing the clutch; anoil pump comprising a pump case fixed to the case and forming a pumpchamber inside and a pump rotor arranged rotatably in the pump chamber,the oil pump being arranged coaxially with the clutch case on one axialside with respect to the clutch case; a first bearing supporting theclutch case at one axial side in a radial direction on the case; and asecond bearing supporting the clutch case at another axial side in theradial direction on the case, wherein a rotor of the rotary electricalmachine is supported by the clutch case, the first bearing comprises anouter wheel, an inner wheel, and rolling elements intervening betweenthe outer wheel and the inner wheel, the clutch case comprises a pumpdrive shaft which extends toward one axial side and is drive-coupled tothe pump rotor, the pump drive shaft is supported on the case via thefirst bearing and the pump case, the pump case comprises a partitionwall partitioning the first bearing and the pump rotor, the partitionwall comprises a drive shaft insertion hole through which the pump driveshaft is inserted, a gap between an outer peripheral face of the pumpdrive shaft and an inner peripheral face of the drive shaft insertionhole is a distribution passage of oil flowing from the pump chamber tothe first bearing, and a distribution passage diameter difference, whichis a difference between a diameter of the outer peripheral face of thepump drive shaft and a diameter of the inner peripheral face of thedrive shaft insertion hole in the distribution passage, is set so thatthe distribution passage functions as a narrowed portion which limits aflow rate of oil.
 2. The hybrid drive apparatus according to claim 1,wherein the distribution passage diameter difference is set larger thana maximum value of an allowance of displacement in the radial directionof the pump drive shaft supported by the first bearing, and thedistribution passage diameter difference is set so that a flow passagesectional area of the distribution passage is smaller than a flowpassage sectional area of a pump flow passage which is formed by a gapbetween the partition wall and the pump rotor and communicates with thedistribution passage.
 3. The hybrid drive apparatus according to claim1, wherein the pump drive shaft is formed in a stepped shape with oneaxial side being a small diameter portion and another axial side being alarge diameter portion, and is arranged so that the inner peripheralface of the drive shaft insertion hole faces an outer peripheral face ofthe small diameter portion, the first bearing is arranged in contactwith an outer peripheral face of the large diameter portion, adifference between a diameter of the large diameter portion and adiameter of the small diameter portion is designated as a pump shaftstep width, and the distribution passage diameter difference is set to avalue larger than a maximum value of an allowance of displacement in theradial direction of the pump drive shaft supported by the first bearingand smaller than the pump shaft step width.
 4. The hybrid driveapparatus according to claim 1, wherein the pump drive shaft comprises asupply oil passage inside that supplies oil to the clutch, the pump casecomprises a section wall which is arranged on the opposite side of thepump rotor from the partition wall in the axial direction and sectionsone axial side of the pump chamber, and a section wall side pump flowpassage formed by a gap between the section wall and the pump rotorcommunicates with the supply oil passage.
 5. The hybrid drive apparatusaccording to claim 1, wherein the clutch case comprises a one-sideradially extending portion arranged on one axial side of the clutch toextend in the radial direction and having a radially inner end portionon which the pump drive shaft is provided, an another-side radiallyextending portion arranged on another axial side of the clutch to extendin the radial direction, and a cylindrical axially extending portionarranged on a radially outer side of the clutch to extend in the axialdirection, the rotary electrical machine is arranged coaxially with theclutch case and the rotor of the rotary electrical machine is fixed incontact with an outer peripheral face of the axially extending portion,the another-side radially extending portion and the axially extendingportion are formed integrally, the one-side radially extending portionand the axially extending portion are joined by welding and integrated,and a joining part by welding is located on a radially outer side withrespect to an inner peripheral face of the rotor.